On Wed, 02 Sep 2009 15:39:28 -0400, Andrei Alexandrescu
<[email protected]> wrote:
I plan to add a Nullable struct to Phobos (akin to C#'s Nullable,
Boost's Optional).
Apparently a good design is to define Optional!T with a minimum of
member functions (ideally none) and have it use the "alias this" feature
to masquerade as a T. That way Optional!T looks and feels much like a T,
except that it supports a function
bool isNull(T)(Optional!T value);
Am I on the right track? If so, what is the name you'd prefer for this
artifact?
I just thought of something else. If you use alias this, then what
happens here?
Optional!int i = null;
int n = i;
If you are counting on i to implicitly cast to the int using alias this,
then this probably won't work right (I would think it should throw or
require an explicit cast). I guess if you alias this to a function (is
that possible yet?) which checks for null first, then you may have better
behavior, but you still should probably require a cast.
-Steve
